Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) forbade "unlawful medicine."
Note: Treatment with an intoxicant or an unlawful medicine without necessity is forbidden, so that the two hadiths may be reconciled.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19682